91 lines
2.5 KiB
C
91 lines
2.5 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2011 Gareth McMullin <gareth@blacksphere.co.nz>
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* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/lm4f/systemcontrol.h>
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#include <libopencm3/lm4f/gpio.h>
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#include <libopencm3/lm4f/uart.h>
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#include <libopencm3/lm4f/nvic.h>
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static void uart_setup(void)
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{
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/* Enable GPIOA in run mode. */
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periph_clock_enable(RCC_GPIOA);
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/* Mux PA0 and PA1 to UART0 (alternate function 1) */
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gpio_set_af(GPIOA, 1, GPIO0 | GPIO1);
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/* Enable the UART clock */
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periph_clock_enable(RCC_UART0);
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/* We need a brief delay before we can access UART config registers */
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__asm__("nop");
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/* Disable the UART while we mess with its setings */
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uart_disable(UART0);
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/* Configure the UART clock source as precision internal oscillator */
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uart_clock_from_piosc(UART0);
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/* Set communication parameters */
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uart_set_baudrate(UART0, 921600);
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uart_set_databits(UART0, 8);
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uart_set_parity(UART0, UART_PARITY_NONE);
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uart_set_stopbits(UART0, 1);
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/* Now that we're done messing with the settings, enable the UART */
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uart_enable(UART0);
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}
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static void uart_irq_setup(void)
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{
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/* Gimme and RX interrupt */
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uart_enable_rx_interrupt(UART0);
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/* Make sure the interrupt is routed through the NVIC */
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nvic_enable_irq(NVIC_UART0_IRQ);
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}
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/*
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* uart0_isr is declared as a weak function. When we override it here, the
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* libopencm3 build system takes care that it becomes our UART0 ISR.
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*/
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void uart0_isr(void)
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{
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uint8_t rx;
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uint32_t irq_clear = 0;
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if (uart_is_interrupt_source(UART0, UART_INT_RX)) {
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rx = uart_recv(UART0);
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uart_send(UART0, rx);
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irq_clear |= UART_INT_RX;
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}
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uart_clear_interrupt_flag(UART0, irq_clear);
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}
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int main(void)
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{
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gpio_enable_ahb_aperture();
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uart_setup();
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uart_irq_setup();
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/*
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* Not worrying about the UART here.
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*/
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while (1) {
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/* Do some other task */
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}
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return 0;
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}
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